I see two processes in the kaplan book for this.
You can either multiply the # of shares by 12 and then divide the sum of those products by 12 to give you figure you need as the divisor in diluted EPS
You can multiply each # of shares by t/12 as you work through the calculation for the divisor.
I do not believe this mathematically creates any differences but I would like some confirmation. I notice that sometimes I get different answers. Is this simply due to calculator mismanagement on my behalf?